On Tuesday, the acting Speaker of the lower house of Congress, Waldir Maranhao, surprised the country when he announced that he had suspended the vote that allowed the impeachment process against her to go ahead.

He said the 17 April vote in the lower house had breached Congress rules. Members had voted overwhelmingly in favour of the impeachment process going ahead.

But within less than 24 hours he had revoked his decision to annul the vote. He gave no reason for his u-turn.

If the Senate votes goes ahead on Wednesday and Ms Rousseff loses it, she will be replaced by Vice-President Michel Temer while the trial lasts.

She says Mr Temer is a traitor who is taking part in a political coup against her democratically elected government.

The president is accused of illegally manipulating finances to hide a growing public deficit ahead of her re-election in 2014, which she denies.